But Lynn didn't permanently entrench access to social media within the Pentagon's endless lists of rules. Due to what Pentagon officials describe as bureaucratic reasons, he instead extended the policy on yet another interim basis, while further reviews with the Policy directorate about the impact of online openness on the military proceed. But there will be no substantive changes until January 2012, thanks to Lynn's extension.

And probably not many after that. "It has taken longer than originally anticipated to get this codified into a [Defense Department] instruction," concedes Bryan Whitman, a Pentagon spokesman. "But I don't anticipate any changes from the principles at all. The default is to permit and utilize social media tools, take action when we have to for bandwidth or security reasons, but the default is to have them open and available to the department."

Pentagon officials swear up and down they Get It on social media. Communications choice of a new generation and all that. Instead of keeping the Pentagon's dedicated social media guru, tweeting is now every office's responsibility. At his confirmation hearing today to be Army chief of staff, Gen. Martin Dempsey said the Army would need to get better at using social media (and online role-playing games!) if it wanted to attract the service's next generation of leaders.

Sometimes the military's experiments in social media have gone awry, like when Marines in Afghanistan scrapped the embed of a team of reportersafter comments on their Facebook page turned out to be a pain. But the Marine Corps isn't even in a social media slouch. It got to a million Facebook fans before any of the other services.

Whitman hopes Lynn's move last week will be the last extension of the social media policy's temporary incarnation. (To be nerdy: it's known as a Directive-Type Memorandum, which gives way to a permanent Issuance.) Bureaucracy may move glacially, but these days world events move, as the chairman of the Joint Chiefs of Staff put it on Tuesday, "at the speed of Twitter." The Pentagon can keep pace or be left hitting refresh.